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PHEVs produce almost five times greater global warming emissions than lab-reported figures indicate, according to a new analysis.

Growing Discrepancy In Lab and Real-World CO2 Output

Statistics reveals that PHEVs release just 19% lower CO₂ than traditional gas and diesel vehicles, based on analysis conducted by a advocacy group. That contrasts sharply with laboratory estimates, which assumed a three-quarters reduction in pollution.

Analysts examined data from in-vehicle energy use monitors of eight hundred thousand vehicles sold in the EU between 2021 and 2023. They found that actual CO₂ output from PHEVs in 2023 were 4.9 times higher than lab figures, up from three and a half times in 2021.

“Real-world emissions are rising, while official figures are falling,” said a lead researcher participating in the report. “This discrepancy is growing and creates a significant issue. As a result, PHEVs pollute nearly as much as petrol cars.”

Key Factors Behind the Emissions Gap

Analysts linked most of the gap to overestimates of the “utility factor” – the ratio of kilometers travelled in electric mode relative to total mileage. They found that only 27% of travel was completed in electric mode, while official estimates assumed 84%.

Even, when running in electric mode, emission levels were significantly higher than lab projections. This occurred because electric motors were not strong sufficient to operate independently, leading to combustion motors using gasoline for nearly one-third of the distance completed in EV mode.

Regulatory and Financial Implications

According to estimates, the underestimation of PHEV CO2 output enabled four major automaker companies to avoid more than €5bn in penalties from 2021 and 2023, by falsely easing compliance with European Union average fleet CO₂ standards.

Furthermore, drivers of PHEVs would pay approximately €500 extra per year in operating costs than would be estimated under laboratory tests.

“The strong claims that automakers like to make about their plug-in hybrid cars are obviously way off the truth,” commented a automotive expert. “Buyers are being misled into believing that by buying a PHEV, they are helping the planet and cutting costs. In reality, PHEVs are little better than regular petrol and diesel vehicles in terms of fuel use, CO₂ production, and operating expenses.”

Political Discussion and Automotive Lobbying

Hybrid cars have recently been drawn again into political debates as carmakers have pressed the EU to weaken CO₂ standards. A planned prohibition on sales of new internal combustion cars in 2035 has faced intense pressure from the automotive industry and resistance from member states with significant car manufacturing.

Some high-level politicians have proposed PHEVs as a potential “flexibility” solution to introduce in the legislation.

One independent energy policy expert, who was unaffiliated with the study, called the report a “very useful addition” after years in which segments of the automotive industry argued there was insufficient information to properly assess actual emissions.

“These findings show, without question, that the difference between official and real-world PHEV energy use and CO₂ emissions is much, much greater than for gasoline or diesel cars,” the expert said. “Any policy changes regarding PHEVs should be implemented with extreme caution and in the light of that data.”